title: An open label Phase I trial of a live attenuated H6N1 influenza virus vaccine in healthy adults.
abstract: BACKGROUND
  We describe the results of an open label Phase I trial of a live attenuated H6N1 influenza virus vaccine (ClinicalTrials.gov Identifier: NCT00734175).
  
  
  RESULTS
  We evaluated the safety, infectivity, and immunogenicity of two doses of 10(7) TCID(50) of the H6N1 Teal HK 97/AA ca vaccine, a cold-adapted and temperature sensitive live, attenuated influenza vaccine (LAIV) in healthy seronegative adults. Twenty-two participants received the first dose of the vaccine, and 18 received the second dose of vaccine 4 weeks later. The vaccine had a safety profile similar to that of other investigational LAIVs bearing avian hemagglutinin (HA) and neuraminidase (NA) genes. The vaccine was highly restricted in replication: two participants had virus detectable by rRT-PCR beyond day 1 after each dose. Antibody responses to the vaccine were also restricted: 43% of participants developed a serum antibody response as measured by any assay: 5% by hemagglutination-inhibition assay, 5% by microneutralization assay, 29% by ELISA for H6 HA-specific IgG and 24% by ELISA for H6 HA specific IgA after either 1 or 2 doses. Following the second dose, vaccine specific IgG and IgA secreting cells as measured by ELISPOT increased from a mean of 0.6 to 9.2/10(6) PBMCs and from 0.2 to 2.2/10(6) PBMCs, respectively.
  
  
  CONCLUSIONS
  The H6N1 LAIV had a safety profile similar to that of LAIV bearing other HA and NA genes, but was highly restricted in replication in healthy seronegative adults. The H6N1 LAIV was also not as immunogenic as the seasonal LAIV.
authors.affiliation: Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, United States. ktalaat@jhsph.edu
authors.forename: Kawsar R
authors.initials: KR
authors.lastname: Talaat
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Karron
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Luke
authors.forename: Bhagvanji
authors.initials: B
authors.lastname: Thumar
authors.forename: Bridget A
authors.initials: BA
authors.lastname: McMahon
authors.forename: Grace L
authors.initials: GL
authors.lastname: Chen
authors.forename: Elaine W
authors.initials: EW
authors.lastname: Lamirande
authors.forename: Hong
authors.initials: H
authors.lastname: Jin
authors.forename: Kathy L
authors.initials: KL
authors.lastname: Coelingh
authors.forename: George
authors.initials: G
authors.lastname: Kemble
authors.forename: Kanta
authors.initials: K
authors.lastname: Subbarao
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D058501:Enzyme-Linked Immunospot Assay; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D009975:Orthomyxoviridae / Q000276:immunology*; D014611:Vaccination / Q000379:methods; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated